The present invention relates to a method for producing an oxide catalyst containing Mo, V, Sb, and Nb, the method including a raw material preparation step of obtaining an aqueous mixed liquid containing Mo, V, Sb, and Nb, an aging step of subjecting the aqueous mixed liquid to aging at more than 30° C., a drying step of drying the aqueous mixed liquid, thereby obtaining a dried powder, and a calcination step of calcining the dried powder, thereby obtaining the oxide catalyst, and a method for producing an unsaturated nitrile or an unsaturated acid by using the catalyst.

A method for producing an oxide catalyst according to the present invention is a method for producing an oxide catalyst containing Mo, V, Sb, and Nb, the method including: a raw material preparation step of obtaining an aqueous mixed liquid containing Mo, V, Sb, and Nb; an aging step of subjecting the aqueous mixed liquid to aging at more than 30° C.; a drying step of drying the aqueous mixed liquid, thereby obtaining a dried powder; and a calcination step of calcining the dried powder, thereby obtaining the oxide catalyst, wherein, in the raw material preparation step and/or the aging step, precipitation of Nb is facilitated by performing at least one operation selected from the group consisting of the following (I) to (III): (I) in the raw material preparation step, the aqueous mixed liquid is prepared by mixing a Nb raw material liquid containing Nb with a MoVSb raw material liquid containing Mo, V, and Sb, wherein ammonia is added to at least one of the MoVSb raw material liquid, the Nb raw material liquid, and the aqueous mixed liquid such that a molar ratio in terms of NH.sub.3/Nb in the aqueous mixed liquid is adjusted to be 0.7 or more, and in the aging step, a temperature of the aqueous mixed liquid is adjusted to more than 50° C.; (II) in the aging step, a temperature of the aqueous mixed liquid is adjusted to more than 65° C.; and (III) in the raw material preparation step, the aqueous mixed liquid is prepared by mixing a Nb raw material liquid containing Nb with a MoVSb raw material liquid containing Mo, V, and Sb, wherein a molar ratio in terms of H.sub.2O.sub.2/Nb in the Nb raw material liquid is adjusted to less than 0.2, and in the aging step, a temperature of the aqueous mixed liquid is adjusted to more than 50° C.

A method for producing an oxide catalyst according to the present invention is a method for producing an oxide catalyst containing Mo, V, Sb, and Nb, the method including: a raw material preparation step of obtaining an aqueous mixed liquid containing Mo, V, Sb, and Nb; an aging step of subjecting the aqueous mixed liquid to aging at more than 30° C.; a drying step of drying the aqueous mixed liquid, thereby obtaining a dried powder; and a calcination step of calcining the dried powder, thereby obtaining the oxide catalyst, wherein, in the raw material preparation step and/or the aging step, precipitation of Nb is facilitated by performing at least one operation selected from the group consisting of the following (I) to (III): (I) in the raw material preparation step, the aqueous mixed liquid is prepared by mixing a Nb raw material liquid containing Nb with a MoVSb raw material liquid containing Mo, V, and Sb, wherein ammonia is added to at least one of the MoVSb raw material liquid, the Nb raw material liquid, and the aqueous mixed liquid such that a molar ratio in terms of NH.sub.3/Nb in the aqueous mixed liquid is adjusted to be 0.7 or more, and in the aging step, a temperature of the aqueous mixed liquid is adjusted to more than 50° C.; (II) in the aging step, a temperature of the aqueous mixed liquid is adjusted to more than 65° C.; and (III) in the raw material preparation step, the aqueous mixed liquid is prepared by mixing a Nb raw material liquid containing Nb with a MoVSb raw material liquid containing Mo, V, and Sb, wherein a molar ratio in terms of H.sub.2O.sub.2/Nb in the Nb raw material liquid is adjusted to less than 0.2, and in the aging step, a temperature of the aqueous mixed liquid is adjusted to more than 50° C.

The present invention relates to a catalyst comprising at least one oxide of vanadium, at least one oxide of tungsten, at least one oxide of cerium, at least one oxide of titanium and at least one oxide of antimony, and an exhaust system containing said oxides.

The present invention relates to a catalyst comprising at least one oxide of vanadium, at least one oxide of tungsten, at least one oxide of cerium, at least one oxide of titanium and at least one oxide of antimony, and an exhaust system containing said oxides.

An object of the present invention is to provide a catalyst ensuring that in the case of causing gas-phase catalytic oxidation of an unsaturated aldehyde and an oxygen-containing gas with use of the catalyst to produce a corresponding unsaturated carboxylic acid, the pressure loss can be kept low and an unsaturated carboxylic acid can be produced with high selectivity. The present invention relates to a ring-shaped or columnar catalyst, which is used at the time of producing a corresponding unsaturated carboxylic acid by causing gas-phase catalytic oxidation of an unsaturated aldehyde and an oxygen-containing gas, wherein the outer peripheral edge part is inclined relative to the center line.

An object of the present invention is to provide a catalyst ensuring that in the case of causing gas-phase catalytic oxidation of an unsaturated aldehyde and an oxygen-containing gas with use of the catalyst to produce a corresponding unsaturated carboxylic acid, the pressure loss can be kept low and an unsaturated carboxylic acid can be produced with high selectivity. The present invention relates to a ring-shaped or columnar catalyst, which is used at the time of producing a corresponding unsaturated carboxylic acid by causing gas-phase catalytic oxidation of an unsaturated aldehyde and an oxygen-containing gas, wherein the outer peripheral edge part is inclined relative to the center line.

Provided are a method for producing hydrocyanic acid and a device for producing hydrocyanic acid, which can improve a yield of the hydrocyanic acid in a vapor phase contact ammoxidation reaction of methanol. The method for producing hydrocyanic acid includes a step of obtaining hydrocyanic acid by a vapor phase contact ammoxidation reaction by supplying a raw material gas including methanol in a fluidized bed reactor (1) through a raw material gas disperser (7) disposed in the fluidized bed reactor (1) and bringing the methanol into contact with ammonia and oxygen in the presence of a metal oxide catalyst, in which the raw material gas disperser (7) has one or more pores for releasing the raw material gas into the fluidized bed reactor (1), and the number of pores per unit cross-sectional area of the fluidized bed reactor (1) is 10 to 45 pieces/m.sup.2.

Provided are a method for producing hydrocyanic acid and a device for producing hydrocyanic acid, which can improve a yield of the hydrocyanic acid in a vapor phase contact ammoxidation reaction of methanol. The method for producing hydrocyanic acid includes a step of obtaining hydrocyanic acid by a vapor phase contact ammoxidation reaction by supplying a raw material gas including methanol in a fluidized bed reactor (1) through a raw material gas disperser (7) disposed in the fluidized bed reactor (1) and bringing the methanol into contact with ammonia and oxygen in the presence of a metal oxide catalyst, in which the raw material gas disperser (7) has one or more pores for releasing the raw material gas into the fluidized bed reactor (1), and the number of pores per unit cross-sectional area of the fluidized bed reactor (1) is 10 to 45 pieces/m.sup.2.

An oxide catalyst to be used for gas-phase catalytic ammoxidation reaction of propane or isobutane, the oxide catalyst comprising a composite oxide, wherein the composite oxide comprises a catalytically active species to be isolated from the composite oxide using a hydrogen peroxide solution, and the catalytically active species has an average composition represented by the following formula (1) in STEM-EDX measurements;

Formula:

Mo.sub.1V.sub.aSb.sub.bNb.sub.cW.sub.dX.sub.eO.sub.n   (1) wherein X represents at least one selected from the group consisting of Te, Ce, Ti, and Ta; a, b, c, and d satisfy relations represented by a formulae of 0.050≤a≤0.200, 0.050≤b≤0.200, 0.100≤c≤0.300, 0≤d≤0.100, 0≤e≤0.100, and a≤c; and n represents a number determined by valences of the other elements.